This is where I have issues. I don't know if manufactured game cards are cheap enough, but I know that for AAA games where the bigger expenses come in, they want physical and want high capacity.
I don't know if Nintendo goes can find big, fast, cheap, and secure. I suspect that they may get creative and do big, slow, cheap, and secure, require installs, and use the card as a proof of ownership.
EDIT: An interesting data point. On DekuDeals, they allow you to filter by digital or physical. They show 13159 digital titles, and 2301 physical titles. That means to me than 17% of titles (or so) are both physical and digital. I don't know what the ratio of garbage shovelware is.